Feature/refactor parse tests

[berkes]

##
# When testing, please use the test helpers `parsed_rebuilt` and `test_string`.
#
# `test_string` merely returns the description of the test.
# `parsed_rebuilt` parses that description and then rebuilds a string from
# the parsed result.
# Most often those should match:
#   expect(parsed_rebuilt).to eql(test_string)
# Sometimes they do not match exactly:
#   expect(parsed_rebuilt).to eql("slightly different outcome")
# TODO: write a matcher that warns when "slightly different outcome" is not
#       different. That way we know we are introducing unexpected duplication.

[Mziserman]

Awesome, thanks !